-LRB- CNN -RRB- -- Reports of young children developing premature or inappropriate sex characteristics have prompted the U.S. Food and Drug Administration to require a boxed label warning on two testosterone gel products .

Men use testosterone gels if they no longer produce testosterone or produce it in low amounts .

The FDA announced Thursday that these children had experienced adverse effects in growth and sexual development after coming into contact with adults who used the products .

Specifically , young girls developed male sex characteristics , and boys prematurely developed male sex characteristics

The gels , AndroGel and Testim , are approved for use in men who produce little or no testosterone . In 2007 , there were 1.4 million prescriptions dispensed for AndroGel -- 25,000 of which were for women -- and 370,000 for Testim .

Some women use testosterone gel products off-label , perhaps to increase sex drive , but the FDA has not approved these products for any reason in women .

Other non-FDA approved products are sold over the Internet . The agency has not reviewed the safety and efficacy of these products and does not know how widely they are sold .

In explaining how a child might have been exposed , Dr. Dianne Murphy , director of the Office of Pediatric Therapeutics at the FDA , suggested that a gel user might forget to wash his or her hands or cover treated areas , or may have not waited for skin to dry , and then picked up the child and held him or her to the upper body .

The ratio of skin surface area to total body size of a child is much greater than in an adult , Murphy said . That means that a small area on an adult 's body corresponds to a greater percentage of surface area on a child 's body .

The FDA has reviewed eight cases of children ages 9 months to 5 years who developed symptoms as a result of exposure to the gel up to December 1 . Abnormal effects included inappropriate enlargement of the genitalia , premature development of pubic hair , advanced bone age , increased libido and aggressive behavior .

Although most children 's signs and symptoms regressed after they were no longer exposed to the gel , in a few cases the enlarged genitalia did not return to normal , and the bone age was still higher than the child 's chronological age , the FDA said .

One of these children required surgical intervention , the FDA said . Some children also had to undergo invasive diagnostic procedures .

More than a dozen additional reported cases are currently under review by FDA .

Androgel is applied to the upper arms and shoulders and abdomen once per day , and Testim is applied to the upper arms and shoulders once per day , said Dr. Mark Hirsch of the FDA . The current labels instruct users to wash their hands after use , and to cover treated skin with clothing .

When product users applied gel to body parts that were not indicated in the product 's labeling , they `` increased the opportunity for a child to be inadvertently exposed , '' she said .

The FDA recommends that children and women avoid contact with the places where men have applied these products . The agency also recommends that adults who use testosterone gels do the following :

• Wash hands with soap and water after every application . • Cover the application site with clothing when gel has dried . • Wash the site where the gel was applied with soap and water before coming into skin contact with another person . • Note that the use of non-FDA-approved testosterone gels that can result the same effects should be avoided .

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AndroGel and Testim approved for use in men who produce little or no testosterone

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Other non-FDA approved products are sold over the Internet

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Women also use these products off-label